Process for preparing 2-halo-5-substituted pyridines

摘要

Described are preferred processes for preparing 2-halo-5-substituted pyridine compounds. Preferred processes can be conducted in a one-step, one-pot fashion, and involve the reaction of a formamide and a halogenating agent with a nitrile such as cis-2-pentenonitrile or with a combination of reactants including an aldehyde such as n-propionaldehyde and a nitrile or an amide. Preferred processes provide for convenient and advantageous preparations of 2-chloro-5-methylpyridine, which serves as an intermediate to important insecticidal compounds.